Learn More
We discuss the rapid growth of films and lithographically templated microstructures of vertically aligned small-diameter multiwalled carbon nanotubes (VA-MWNTs), by atmospheric-pressure thermal chemical vapor deposition (CVD) of C2H4/H2/Ar on a Fe/Al2O3 catalyst film deposited by electron beam evaporation. The structures grow to 1 mm height in 15 min and(More)
This paper reports the design, fabrication and testing of a thermally-actuated bistable MEMS relay. Mechanical bis tability ensures zero actuation power in both the on and off states, and permits actuation with a transient thermal actuator. In the off state, this relay stands off more than 200 V. In the on state, it exhibits a minimum total resistance of 60(More)
This paper presents a monolithic mechanically-bistable mechanism that does not rely on residual stress for its bistability. The bistable mechanism comprises two centrally-clamped parallel beams that have a curved shape but no residual stress after fabrication. Modal analysis and FEA simulation of the beams are used to predict and design the bistable(More)
This thesis first develops a bistable mechanism that does not rely on internal stress or hinges for its bistability, which is then combined with transient electrothermal actuation and contact structure to develop a MEMS relay for power switching. The relay components, fabricated by a through etch of a silicon wafer using deep reactive ion etch (DRIE), move(More)
Insertion of trocars, needles, and catheters into unintended tissues or tissue compartments results in hundreds of thousands of complications annually. Current methods for blood vessel cannulation or epidural, chest tube, and initial trocar placement often involve the blind pass of a needle through several layers of tissue and generally rely on(More)
This paper describes Robopsy, an economical, patient-mounted, telerobotic, needle guidance and insertion system, that enables faster, more accurate targeting during CT-guided biopsies and other percutaneous interventions. The current state of the art imaging technology facilitates precise location of sites within the body; however, there is no mechanical(More)
Development and evaluation of a new image-based user interface for robot-assisted needle placements with the Robopsy system," copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
The exceptional electronic, thermal, and mechanical properties of carbon nanotubes (CNTs) have motivated extensive research on their manufacturing and applications. At bulk scales, there is particular interest in property enhancements by adding CNTs to polymers to make composite materials. Most work on CNT-based composites presented in the literature to(More)
In poorly constrained extra-vascular environments such as hollow viscera, current catheter navigation techniques are restricted to simple paths and therefore limit a doctor's ability to position the catheter. This paper presents a new catheter positioning system that enables faster and more accurate catheter placement, with fewer scans. The proposed robotic(More)